It's not "my opinion" only, but is the opinion of many whom have good reasons for holding that view, inclusive of a Franciscan priest who's order had centuries ago had custody of the artifact, until that artifact was taken away from them, and given over to the Dominicans --- if memory serves correct.
Do you not know also of the Virgin of Guadalupe Extremadura (Spain)?
Go look that one up> I could provide a link, for a decent place to begin one's own investigation -- but why should I?
Yet when or if you were to look upon image of that statue, she does have a dark face.
Men such as Columbus, (and many other New World explorers whom set off from Spain made pilgrimage to that statue)-- some time right before he sailed away to the West, on his first voyage.
There were paintings of that statue also, imagery or likeness of that icon.
The Mexican Guadalupe image bears striking resemblance to other Marian imagery of that era, which paintings also resembled and can traced in similarity to European/Middle Eastern paintings of yet greater antiquity.
It does not take a highly trained art historian, to be able to trace the 'art' aspect influences --- which quite likely made their way to Mexico almost as in form of token/talisman-like imagery that the one whom the Franciscan identified as Marcos the Indian was the one whom either painted the original image, or else other later and unnamed persons repainted the image as seen today.
There is said by some of the college student who participated in the [ahem] research that a Hispanic and Roman Catholic college professor engaged in, that there had been an original, and cruder image which had been painted over with a white paste of sorts, with that image having also been retouched upon numerous occasion.
Yet one will not find information of that sort (other than in possibly less-than-fully-truthful presentation) at any of dozens of web pages devoted to the image, and to "Mary".
So--- if you would like to find out the truth, then I will suggest that one engage in a diligent search for it -- beyond all the place where it is being promoted.
By which I mean, once it is known what the alleged details are, from there one need see if those same could be made subject to falsification.
In other words -- test the claims.
Which is far, far different that looking only for reassurance for what one desires to be true...
A bishop of Mexico City -- right about the time this Juan Diego person was canonized did so, but boy howdy, it cost him a great deal with that being yet more demonstration that "the church of frauds" as the Orthodox referred to Rome in regards to the various forged documents those of Rome produced (but many of Rome, themselves not knowing any better, did themselves accept) in support of the concept of there allegedly the bishop of Rome, that pope there, and not other "popes" was always pope over all from the earliest Church universal. The Orthodox protested, and still do, but do so quietly and circumspectly.
I could say more which runs contrary to that which is otherwise much repeated in varied ways concerning the image and it's history -- but again -- why should I bother?